As the applications for robotic end effectors such as robot hands have grown, so has grown the need for a simple, easily maintainable and controllable robot hand which provides a conformable grasp suitable for grasping a wide variety of objects. Prior art configurations have so far failed to provide such desired simplicity.
Among prior art robot hands, a common approach has been to attempt to control each finger joint individually. This typically involves discrete actuators, feedback regarding relative position of phalanges at the joint, and control commands for each actuator. The actuator commands are typically generated in response to a known geometry for an object to be grasped. Thus, a controller must compute the appropriate drive commands for each actuator, and must attempt to compensate for misalignment of the object during a grasping operation.
Obviously, providing discrete actuators and control capability for each joint is a complex design choice. One attempt at providing a robot hand having a conformable grasp employs individual clutch mechanisms at each joint. Implementation of the design is difficult as heightened levels of grasping force are required to alter the relative positions of the individual phalanges. Further, the clutches are prone to mechanical failure.
A further attempt at providing a robot hand with a conformable grasp involves fingers comprised of parallel, pliant pneumatic cylinders. However, this hand has been implemented with only eight discrete finger positions, thus limiting the ability of the hand to successfully conform the fingers to a variety of objects to be grasped.